C# - Communicate with WinUSB device with LIBUSB

Question

I am trying to communicate with a Nokia Lumia phone(RM-917), over USB using LIBUSING and C#. LIBUSB is able to see the device's information(pid,vid,etc). However, I am not able to successfully write to ANY endpoint, even sending the exact command as the Windows Device Recovery Tool.

According to WinUSB, the write endpoint is EP07, however, this endpoint just times out. I have tried every other endpoint, and all of these fail.

`
public void initDevice()
{


    if(this.lumiaDevice == null)
    {
        throw new Exception("LumiaPhoneManager does not have a selected device");
    }

    UsbDeviceFinder MyUsbFinder = new UsbDeviceFinder(0x0421, 0x0661);
    MyUsbDevice = UsbDevice.OpenUsbDevice(MyUsbFinder);


    IUsbDevice wholeUsbDevice = MyUsbDevice as IUsbDevice;
    if (!ReferenceEquals(wholeUsbDevice, null))
    {
        // This is a "whole" USB device. Before it can be used, 
        // the desired configuration and interface must be selected.

        // Select config #1
        wholeUsbDevice.SetConfiguration(1);

        // Claim interface #0.
        wholeUsbDevice.ClaimInterface(1);
    }

    if (this.writer == null)
    {
        writer = MyUsbDevice.OpenEndpointWriter(WriteEndpointID.Ep07);
    }



}


    public void readPCode()

{
    currentID++;
    var _x = new jsonPkt();
    ErrorCode ec = ErrorCode.None;
    int bytesWritten;
    _x.id = this.currentID + 1;
    _x.method = "ReadProductCode";

    string value = @"{""jsonrpc"":""<JSONRPC>"",""id"":<ID>,""method"":""<METHOD>"",""params"":null}";
    value = value.Replace("<JSONRPC>", "2.0");
    value = value.Replace("<ID>", currentID.ToString());
    value = value.Replace("<METHOD>", _x.method.ToString());


ec = writer.Write(Encoding.Default.GetBytes(value), 8000, out bytesWritten);
    currentID++;

    if (ec != ErrorCode.None) throw new Exception(UsbDevice.LastErrorString);

    byte[] readBuffer = new byte[1024];
    while (ec == ErrorCode.None)
    {
        int bytesRead;

        // If the device hasn't sent data in the last 100 milliseconds,
        // a timeout error (ec = IoTimedOut) will occur. 
        ec = reader.Read(readBuffer, 100, out bytesRead);

     //   if (bytesRead == 0) throw new Exception("No more bytes!");

        // Write that output to the console.
        this.rtb.Text += Encoding.Default.GetString(readBuffer, 0, bytesRead).ToString() + "\n";

    }
}

Answer 1

Found the solution

Debugged the OEM software and found the program was using a different path to the USB device. After that I was getting access denied errors, which was solved by moving the project to a different drive. For reasons unknown, when the program runs on c drive, the CreateFile function fails with access denied